Is radon high in Billings, Montana?

Moderate. Averaging the model's ZIP-code predictions across Billings (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 2.9 pCi/L - about 1.6× the US average of 1.8 and close to the Montana average of 3.1. That is in the 2-4 pCi/L range where the EPA says to consider fixing. Billings ranks 1 of 4 Montana cities on this site.

Which Billings ZIP codes have the highest radon?

Predictions for the 4 modeled ZIP codes in Billings range from 2.9 to 3.1 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 100% at or above 2. The city is fairly uniform, so the city-wide number is a reasonable guide for any neighborhood.

Should I test for radon in Billings?

Yes, soon. With a predicted basement average of 2.9 pCi/L, a meaningful share of Billings homes will test above the 4 pCi/L action level. Start with a short-term kit; if it reads 2 or higher, confirm with a long-term test or a continuous monitor before paying for mitigation.

What does EPA Radon Zone 2 mean for Billings?

Billings sits mainly in Yellowstone County, which the EPA classifies as Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and covers whole counties. The 2001-2021 model agrees with the zone for the city. Neither replaces a test of your own home.

Radon levels in Billings, Montana

ModerateEPA Zone 2

Predicted long-term basement average of 2.9 pCi/L (model estimate) across the 4 modeled ZIP codes in Billings - about 1.6× the US average of 1.8, close to the Montana average of 3.1. Ranked #1 of 4 Montana cities on this site. Most of the city lies in Yellowstone County.

Test Billings, MT - the EPA says "consider fixing" in this range

The predicted basement average here is 2.9 pCi/L, in the 2-4 pCi/L band where the EPA recommends considering mitigation. Plenty of individual homes in a moderate area test above 4. Start with a short-term test; if it comes back at 2 or higher, follow up with a long-term test or a continuous monitor.

Get a short-term test kit →Or track it with a continuous monitor

Already tested at 4 pCi/L or higher? Find a certified mitigation professional (EPA). A mitigation system typically runs $800-$2,500 installed.

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Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.

2.9 ± 0.07

pCi/L predicted basement mean (model SD)

1.8 ± 0.06

pCi/L predicted upstairs (above-ground) mean

2.9-3.1

range of ZIP-level basement predictions in the city

of Billings ZIPs predicted ≥ 4 pCi/L (100% ≥ 2)

What this means for Billings

The typical Billings home is predicted in the 2-4 pCi/L band. The EPA's guidance for this range is to consider fixing, because there is no known safe level and a meaningful minority of homes in a moderate area will test above 4.

The city figure is not a separate estimate: it is the mean of the model's ZIP-code predictions, weighted by the share of the city's land in each ZIP (Census 2020 ZCTA-to-place relationship file). The 1993 EPA zone (2) for Yellowstone and the 2001-2021 model agree here.

Comparable Montana cities: Missoula (2.9), Great Falls (2.5), Bozeman (2.3), Boise (2.4).

ZIP codes in Billings

ZIPs that overlap the city, largest share of its land first. Predicted basement and upstairs means are model estimates; ZIPs the model does not cover show a dash.

ZIP	Share of city	Basement	Upstairs	Grade
59102	32%	2.9 ± 0.07	1.9	Moderate
59105	28%	2.9 ± 0.05	1.6	Moderate
59101	24%	3.1 ± 0.08	1.9	Moderate
59106	16%	2.9 ± 0.06	1.8	Moderate

Testing help in Montana

Montana's radon program page is at deq.mt.gov and, when we checked it, offered free short-term kits for child-care providers through the Choose Safe Places program. EPA state radon contacts page. If a test comes back at 4 pCi/L or higher, mitigation typically costs $800-$2,500 installed; use EPA find-a-professional and read the mitigation guide.

Billings radon questions

Is radon high in Billings, Montana?: Moderate. Averaging the model's ZIP-code predictions across Billings (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 2.9 pCi/L - about 1.6× the US average of 1.8 and close to the Montana average of 3.1. That is in the 2-4 pCi/L range where the EPA says to consider fixing. Billings ranks 1 of 4 Montana cities on this site.
Which Billings ZIP codes have the highest radon?: Predictions for the 4 modeled ZIP codes in Billings range from 2.9 to 3.1 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 100% at or above 2. The city is fairly uniform, so the city-wide number is a reasonable guide for any neighborhood.
Should I test for radon in Billings?: Yes, soon. With a predicted basement average of 2.9 pCi/L, a meaningful share of Billings homes will test above the 4 pCi/L action level. Start with a short-term kit; if it reads 2 or higher, confirm with a long-term test or a continuous monitor before paying for mitigation.
What does EPA Radon Zone 2 mean for Billings?: Billings sits mainly in Yellowstone County, which the EPA classifies as Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and covers whole counties. The 2001-2021 model agrees with the zone for the city. Neither replaces a test of your own home.

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